And make no mistake. Getting him out of the way is a good thing. He was a really nasty character, and while I'd rather see him on trial than on a slab, either is preferable to continuing to run his terror operation.
That said, I think it's very likely that his importance to al Qaeda has been consistently exaggerated by the Bush administration and that his removal will have a much lower-than-expected effect on the insurgency as a whole. Remember, Zarqawi was not an Iraqi. At best, he was like a mob capo brought in from another city to run part of an operation.